Web resources such as web pages and web sites have geographic serving areas associated with them. A serving area represents the geographic distribution of users who are interested in the web resource. A serving area, alternatively, may be considered to represent the geographic area that the web resource intends to reach. For example, a web page that lists houses for sale within a city may have a serving area of the county that contains the city. As another example, a web page with general information, such as an introduction to mathematics, is likely of interest to users from any location and thus has a serving area of the entire world.
Many location-based web applications have been developed to support mobile devices and local searching needs. Such location-based web applications include navigation systems, location-based search systems, local advertisement systems, geographic retrieval systems, and so on. These web applications typically need to detect the serving area of a web resource and match it with the user's current location. For example, a cellular phone user may want to find a local car dealership. A web application could match the user's current location as indicated by the cellular phone with the serving area of car dealers to identify which car dealerships may be appropriate to suggest to the user.
Typically, web applications search web resources for location information (e.g., city names) and use that information when determining whether the web resource matches the user's location. A difficulty with such web applications is that location information of a web resource may have different purposes and thus different meanings. For example, a web page for a Chinese restaurant may contain the geographic locations “Peking” and “Redmond.” The geographic location of Peking indicates that the subject of the web page is somehow related to China, but the geographic location of Redmond indicates that the restaurant is located in Redmond, Wash., USA. If a web application is trying to match the user's current location, which may be in Beijing, to the location of the web page, the web application might erroneously determine that the serving area is Beijing. In such a case, the web application might suggest a restaurant in Redmond, Wash. to a user in Beijing.